The chart shows the average daily minimum and maximum levels of air pollutants in 4 cities 2000

The given bar chart presents the daily minimum and maximum levels of SO2 and N2O which caused pollution in 4 different cities (Los Angeles, Calcutta, Beijing and Mexico City) in the year 2000. Overall, Mexico City was by far the most contaminated by the two mentioned pollutants among the four cities.

In Los Angeles, the quantity of SO2 emitted into the atmosphere was the lowest of all cities, with a minimum average of 2 micro-grams per m3 and a maximum average five times as much, at 10 micro-grams. The levels of N2O emissions were much higher with the maximum daily average level reaching up to more than 100 micro-grams per m3. Meanwhile, the atmosphere in Mexico City was severely polluted by SO2 and N2O emissions with the daily minimum and maximum averages of 80 and 113 micro-grams per m3 respectively.

In contrast to Los Angeles and Mexico City, the amount of pollution caused by N2O in Calcutta and Beijing was less than that caused by SO2. The daily average maximum figures for SO2 emissions were 59 micro-grams per m3 in Calcutta and 130 micro-grams per m3 in Beijing while the average maximum figures for N2O were just over 50 micro-grams per m3 in both cities.